How to write a Custom Action

  1. Write a class inherited from mistral.actions.Action

from mistral_lib import actions

class RunnerAction(actions.Action):
    def __init__(self, param):
        # store the incoming params
        self.param = param

    def run(self, context):

        # Actions can be returned in a manner of ways. The simplest is
        # return {'status': 0}
        # or using a Result object. The Result has an optional parameter data
        # that can be used to transfer information
        return actions.Result()
        # Failed executions can also be returned using a workflow Result object
        # that contains an non empty error parameter such as:
        # return actions.Result(error="error text")

  1. Publish the class in a namespace (in your setup.cfg)

[entry_points]
mistral.actions =
    example.runner = my.mistral_plugins.somefile:RunnerAction

  1. Reinstall your library package if it was installed in system (not in virtualenv).

  2. Run db-sync tool to ensure your actions are in Mistral’s database

$ mistral-db-manage --config-file <path-to-config> populate

  1. Now you can call the action example.runner

my_workflow:
  tasks:
    my_action_task:
      action: example.runner
      input:
        param: avalue_to_pass_in